"Oils" is a collective term for more or less viscous, generally organic-chemical liquids. Depending on their chemical composition, a distinction may be drawn between fatty, essential, mineral and silicone oils. Fatty oils include liquid, semisolid and solid products of vegetable and animal origin. They are also known as sweet oils.

Castor oil is of vegetable origin and is obtained from the seeds of the castor-oil plant by hot or cold pressing. Castor oil is not an edible oil but rather a high-quality lubricating oil. Castor oil is indigestible to humans.

Quality / Duration of storage

The acid value of an oil may be used as a measure of quality. However, the acid value of the oil must not be too high, as this denotes an excessively high content of free fatty acids, which causes the oil to turn sour. Discoloration may also occur. Castor oil should have an acid value of at most 1%.

Oils and fats spoil by readily becoming rancid. Rancidity is promoted by light, atmospheric oxygen and moisture and leads to changes in odor and taste. Thus, the tanks and barrels must be filled as full as possible, taking into consideration the coefficient of cubic expansion (see Density), so that as little ullage space as possible is left above the cargo. Do not load rancid oil, since it does not meet quality requirements.

Do not accept for loading castor oil contaminated by ferrous and rust particles or by seawater.

Maximum duration of storage is as follows:

Temperature

Max. duration of storage

Source

12 - 25°C

6 months

[1]

Intended use

Castor oil is used as a lubricating oil, in medicine, in the chemical, leather and textile industries and in cosmetics.

Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Normally, the oil does not need to be heated, since its solidification point is relatively low. However, if temperatures should arise during the voyage which are in the solidification range, the following must be noted: to be able to pump the oil out of the tanks, it must be at the required pumping temperature. This is only possible, however, if the oil has been kept liquid during the voyage (above a minimum temperature). Loading, travel and pumping temperatures must be precisely complied with, since any change in consistency which occurs during transport may prove irreversible.

If the oil solidifies in the tanks, it cannot be liquefied again even by forced heating. In the vicinity of the heating coils, the oil melts, scorches, discolors and becomes rancid.

Pumping out may be difficult in cold weather. The oil may cool too rapidly in the long lines and solid deposits form on the outer walls, which cannot be pumped out and prevent the still liquid cargo from reaching the suction valve. This problem can be solved by appropriate heating or insulation of the lines.

Where the oil is packaged in barrels, the latter have to be handled with appropriate care. Damaged barrels quickly lead to oil leakage and thus to loss of volume or to damage to other parts of the cargo.

All fats and oils have a particular density (approx. 0.9 g/cm3). With a rise in temperature, however, density diminishes, thereby leading at the same time to an increase in volume. This behavior is described by the coefficient of cubic expansion and is known as thermal dilatation.

The coefficient of cubic expansion amounts to: g = approx. 0.0007°C-1

As a rule of thumb, oils may be expected to increase in volume by 1% of their total volume for each 14°C temperature increase.

When filling the barrels or tanks, attention must however be paid to the expansion behavior of the cargo in the event of a rise in temperature (risk of bursting of barrels).

In the case of liquid cargoes, it is important for the ullage space above the cargo to be as small as possible, so that only slight movement of the cargo is possible. Movement in liquid cargoes may have a negative effect on the stability of the means of transport (e.g. during cornering in the case of trucks and trains or when ships roll and pitch).

Barrels have to be secured in such a way that they cannot slip in the hold or on the loading area and suffer damage.

The solidification temperature is of considerable significance in the transport of fatty oils and fats. They must remain liquid during loading, during the voyage and during unloading. Chill haze (separation) begins if cooling causes the temperature of the oil to approach solidification point, the oil becoming ointment-like and finally solid, such that it is no longer pumpable.

Separation and the associated change in consistency from liquid to solid occurs more readily upon cooling, the higher is the solidification point.

The oils must only be heated by a few °C per day, otherwise the risk of rancidity and other negative changes arises.

The following Table merely constitutes a rough estimate of appropriate temperature ranges. Temperatures may deviate from these values, depending on the particular transport conditions.

Designation

Temperature range

Source

Travel temperature

(favorable temperature range)

15°C (12 - 25°C)

[1]

Solidification temperature

-10 - -18°C

[1]

Pumping temperature

30 - 35°C

[2]

Under normal transport conditions, castor oil is liquid and therefore need not be heated. However, if extremely low temperatures should arise during the voyage which are in the solidification range, the oil has to be heated to prevent losses in quality and to achieve pumpability.

The travel temperature must be complied with as far as possible during transport, to minimize oxidation processes.

Fats and fatty oils are insoluble in water. However, contact with water may give rise to soluble lower fatty acids and glycerol, which cause rancidity together with changes in color (yellow to brown), odor and taste as well as gelling and thickening. Castor oil spoils on contact with water. For this reason, the tanks must be absolutely dry after cleaning.

Leaking oil leads to massive contamination and may make whole cargoes unusable.

Of considerable significance with regard to tank cleaning is the iodine value, which is a measure of how strong a tendency the oil has to oxidation and thus to drying. Drying is particularly detrimental to tank cleaning, as the oil/fat sticks to the walls and can be removed only with difficulty. On the basis of drying capacity, oils are divided into nondrying, semidrying and drying oils.

With an iodine value of 81 - 100, castor oil is a nondrying oil, which means that it does not dry significantly on contact with atmospheric oxygen and the tanks are easily cleaned.

Passive behavior

Castor oil is sensitive to contamination by ferrous and rust particles and water (especially seawater).

The tanks or barrels must be clean and in a thoroughly hygienic condition before filling.